Anti-homocitrullinated protein antibody isotype usage in rheumatoid arthritis and their unaffected first-degree relatives.
Bibliographic record
Abstract
OBJECTIVES: The majority of rheumatoid arthritis (RA) patients express anti-citrullinated protein antibodies (ACPA). Unaffected first-degree relatives of RA patients (FDR) also express ACPA, commonly of the IgA isotype. IgG anti-homocitrullinated/carbamylated protein antibodies (AHCPA) have been detected in both RA and FDR. It is unknown whether other isotypes are expressed. We aim to investigate the AHCPA isotype profile in unaffected FDR of RA patients. METHODS: The enrolled subjects were examined by a rheumatologist. FDR and healthy controls (HC) were excluded if they had swollen joints. Serum AHCPA targeting homocitrullinated fibrinogen was determined using enzyme linked immunoabsorbant assay (ELISA). FDR were genotyped for HLA-DR4 alleles encoding the shared epitope (SE). RESULTS: 125 RA (35 probands), 61 FDR and 40 HC were included. 20% of FDR expressed IgG AHCPA, compared to 30% in RA patients and 5% in HC (p=0.0010 for RA vs. HC). Levels of IgG AHCPA in FDR were similar to RA. FDR rarely expressed IgM (8%) and did not express IgA AHCPA. 20% of RA and 13% of HC subjects expressed IgM, but very few expressed IgA AHCPA (<7% in both groups). AHCPA expression in FDR was not significantly associated with joint symptoms, smoking or SE. CONCLUSIONS: IgG AHCPA is the most commonly expressed isotype in RA and FDR. The significance of IgG AHCPA in FDR is unclear as it was not associated with joint symptoms or other risk factors for RA. Longitudinal studies are needed to determine whether AHCPA is meaningful in populations at risk for RA.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".